The present invention relates to a paper feed apparatus used in a copying machine for feeding paper.
A large-capacity feeder (hereinafter referred to as LCF) is an apparatus that can singly store 3,000 to 4,000 paper sheets. The frequency of paper supply can be reduced by storing the LCF with paper sheets of a size that is used frequently.
In this LCF, a paper carrying tray is moved up and down by means of an elevator mechanism, and a paper feed section feeds the uppermost one of paper sheets on the tray.
If a door of the LCF is opened for paper supply, however, the paper carrying tray moves to its lowest position so that paper can be inserted.
If the number of paper sheets to be supplied is small, however, the paper carrying tray moves to the lowest position when the door is opened for paper supply. After the paper supply, therefore, it takes time for each paper sheet to be situated in a paper feed position.
If the paper carrying tray has a storage capacity of 4,000 sheets, for example, paper supply cannot be started unless the tray is raised by a margin corresponding to 3,500 sheets when it is supplied with only 500 sheets, which is very wasteful.
Thus, it takes a lot of time to start copying if a small quantity of paper is supplied to the large-capacity paper feed apparatus in a copying machine.